A survey of the current status of luminescence research was published by Ferd Williams in Jan., 1979, entitled "New Trends in Luminescence Research", Journal of Luminescence 18/19 (1979) pp. 941-946, North-Holland Publishing Company. The applicants have disclosed some details of their instant invention in an article entitled "A New Thin-Film Electroluminescent Material--ZnF.sub.2 :Mn", published by the American Institute of Physics in Applied Physics Letters 35 (9), Nov. 1, 1979.
High-field collision excitation electroluminescence (EL) has become a current area of active research as a result of the application of thin-film technology to form relatively stable EL devices with power efficiencies approaching 1% and with hysteresis in the brightness-voltage characteristic permitting information storage as well as display, as disclosed by T. Inoguchi and S. Mito in Topics in Applied Physics, edited by J. Pankove (publisher Springer, Heidelberg, 1977), Vol. 17, Chapter 6, p. 202. The major research has involved evaporated ZnS:Mn sandwiched between sputtered or electron-beam evaporated Y.sub.2 O.sub.3, as taught by V. Marrello, W. Ruhle, and A. Onton in Applied Physics Letters, 31, p. 452 (1977) and J. M. Hurd and C. N. King in J. Electron. Mater. Vol. 8, No. 6 pages 879-890 (1979). Similar devices have been made with ZnSe:Mn, refer J. Shak and A. E. DiGiovanni, Applied Physics Letters, 33, p. 995 (1978). Related work has beem reported on crystals of CdF.sub.2 :Mn in MIS structures, refer T. Langer, B. Krukowska-Fulde, and J. M. Langer, Applied Physics Letters, 34, p. 216 (1979). Finally, EL has been studied with rare earth dopants in place of Mn in these materials, as described by J. Benoit, P. Bennalloul, R. Parrot and J. Mattler, J. Lumin., 18/19, p. 739 (1979). In all of the foregoing, a high temperature postgrowth anneal is required.